► Tillage selects species according to size, life forms, seed weight and dispersal. ► Herbicides filter species according to their germination and flowering phenology. ► Species on the increase have ...a large germination and flowering range.
Two large-scale weed surveys conducted on winter wheat crops in France in the 1970s and the 2000s were used to determine the influence of management on weed communities. A trait-based approach was used to identify the mechanisms associated with the changing status of arable weeds over a 30 year period.
A three-table ordination method (RLQ analysis) of the data set was performed to relate the environmental table to the species trait table using a species composition table to extract the joint structure (synchronic analysis). We then conducted a diachronic analysis to investigate the relationship between traits, alone or in combination, and the changing status of weeds.
The synchronic analysis showed that tillage intensity filtered weeds according to height, seed weight, life forms and dispersal. Conversely, herbicides selected for species with delayed germination, which allows them to escape herbicide treatments. The diachronic analysis showed that successful weeds that have expanded were small plants, with rather light seeds, that can germinate over a long time frame during the vegetative period. This trait syndrome was probably favoured by profound changes in crop rotation and by increasing herbicide pressure. Our approach provides an excellent example of how future shifts in weed communities can be predicted and hence how weed management can be adapted so as to avoid promoting selection of problematic weeds.
Neural connections of the seventh cranial nerve with its neighboring nerves are common and well documented; however, communication with ansa cervicalis is as yet unknown. We present a case with such ...a connection found during cadaveric dissection, with hitherto unknown consequences. In this specimen, after giving the marginal mandibular and cervical branches, the cervicofacial division continued distally to communicate with the distal loop of ansa cervicalis. Presence of such connection may result in facial muscle paralysis on injury to the ansa or strap muscle paralysis on injury to the facial nerve, depending on the direction of nerve fibers. Such unusual connections bring to light the need for extreme care during surgeries in the neck to safeguard any such connections and when using the ansa as donor.
Although Glyphosate-based herbicides are often marketed as environmentally friendly and easily biodegradable, its bioavailability and risks to wildlife raise significant concerns. Among non-target ...organisms, earthworms which live in close contact with the soil can be directly exposed to pesticides and harmed. We investigated soil contamination and the exposure of earthworms to glyphosate, its metabolite AMPA, and glufosinate in an arable landscape in France, both in treated (i.e. temporary grasslands and cereal fields under conventional farming), and nontreated habitats (i.e. hedgerows, permanent grasslands and cereal fields under organic farming) (n = 120 sampling sites in total). Glyphosate, AMPA and glufosinate were detected in 88%, 58% and 35% of the soil samples, and in 74%, 38% and 12% of the earthworm samples, respectively. For both glyphosate and AMPA, concentrations in soils were at least 10 times lower than predicted environmental concentrations. However, the maximum glyphosate soil concentration measured (i.e., 0.598 mg kg−1) was only 2 to 3 times lower than the concentrations revealed to affect earthworms (survival and avoidance) in the literature. These compounds were found both in conventional and organic farming fields, thus supporting a recent study, and for the first time they were detected in hedgerows and grasslands. However, glyphosate and AMPA were more frequently detected in soils from cereal fields and hedgerows than in grasslands, and median concentrations measured in soils from cereal fields were significantly higher than in the two other habitats. Bioaccumulation of glyphosate and AMPA in earthworms was higher than expected according to the properties of the molecules. Our findings raised issues about the high occurrence of glyphosate and AMPA in soils from cropped and more natural areas in arable landscapes. They also highlight the potential for transfer of these molecules in terrestrial food webs as earthworms are prey for numerous animals.
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•Glyphosate, AMPA, and glufosinate were measured in 120 soils and earthworms.•Glyphosate was detected in 88% and 74% of the soil and earthworm samples, respectively.•Soil concentrations of glyphosate were at least 10 times lower than PECs.•Mean soil concentrations were not influenced by pesticide use or cropping systems.•Bioaccumulation of glyphosate and AMPA was higher than expected by molecule properties.
Summary
Integrating principles of ecological intensification into weed management strategies requires an understanding of the many relationships among weeds, crops and other organisms of ...agro‐ecosystems in a changing context. Extensively used during the last two decades in weed science, trait‐based approaches have provided general insights into weed community response to agricultural practices, and recently to understanding the effect of weeds on agro‐ecosystem functioning. In this review, we provide a holistic synthesis of the current knowledge on weed response and effect functional traits. Based on the literature and recent advances in weed science, we review current knowledge on (i) weed functional groups and ecological strategies, (ii) weed functional response traits to cropping systems and (iii) weed functional effect traits affecting agro‐ecosystem functioning. For each functional trait, we explicitly present the assumptions and evidence on the linkage between trait values and ecological functions, in response to either management practices, for example tillage, sowing and herbicides, or biotic interactions, for example crop–weed competition and pollination. Finally, we address and discuss major research avenues that may significantly improve the use of traits and the knowledge of functional diversity in weed science for the future, especially to design and implement more environmentally sustainable weed management strategies.
Summary
Seed predation by natural predators can contribute to the regulation of the weed seedbank, hence has been acknowledged as a promising way to significantly reduce the use of chemicals and ...mechanical weeding to manage arable weeds. However, the complex aspects that determine seed species preference are not yet fully understood, especially, the relationship between weed seed traits and the feeding behaviour of seed predator species. In this study, we examine predation on 42 weed species by four ground beetle species as a function of two major seed traits: seed mass and seed lipid content. We used an _original experimental design to create a statistically independent trait value distribution for evaluating the separate and interactive effects of these two traits. Our results show that all the ground beetles species consumed weed seeds, but at different rates. The smallest weed seeds with high lipid content were among the most consumed. While seed mass might be limiting for ground beetles, due to ease of handling or the thickness of the seed coat, they may preferentially consume seeds rich in lipids to increase energy uptake. To our knowledge, this study is the first to reveal that two major seed traits drive seed predation by ground beetles.
Ground penetrating radar (GPR) is used to detect the underground buried objects for civil as well as defence applications under varying conditions of soil moisture content. The capability of ...detection depends upon soil moisture, target characteristics and subsurface characteristics, which are mainly responsible for contaminating the GPR images with clutter. Researchers earlier have used averaging, mean, median, Eigen values, etc. for subtracting the background from GPR images. To analyse the background subtraction or clutter reduction problems, in this paper, we have experimentally reviewed background subtraction techniques with or without target conditions to enhance the target detection under variable soil moisture content. Indigenously developed GPR has been used to collect the data for different soil conditions and several background subtraction signal processing techniques were critically reviewed like, mean, median, singular value decomposition (SVD), principal component analysis (PCA), independent component analysis (ICA) and training methods. The signal to clutter ratio (SCR) measurement has been used for performance evaluation of each technique. The relative merits and demerits of each technique has also been analysed. The background subtraction techniques have been appliedto experimental GPR data and it is observed that in comparison of mean, SVD, median, ICA, PCA, the training method shows the highest SCR with buried target. Finally, this review helps to select the comparatively better background subtraction technique to enhance the detection capability in GPR.
Maintaining a refugia i.e. a proportion of the population that is not exposed to selection by treatments has been suggested as an alternative to mass treatment in the management of nematode parasites ...of sheep. Three refugia have been identified: nematodes in untreated hosts, encysted larvae and free-living stages on pastures. Here we tested whether Targeted Selective Treatments (TST) could be relevant in controlling nematode infections and delaying anthelmintic resistance selection. We first conducted a one grazing season experiment to compare all flock treatment (the whole flock was treated monthly) and TST based on monthly excretion eggs and daily weight gain. Nematode burden was higher in TST group, but anthelmintic susceptibility of nematodes was preserved. We then used an individual-based model to evaluate the sustainability of TST on a longer period. The simulation approach indicated that TST20% and TST30% of the flock were efficient both at maintaining resistance at a low level and controlling nematode parasite infections on a mid-term period (i.e. simulation of five grazing seasons). However for an efficient TST, these percentages of treated hosts should be adapted to flock size since the number of nematode parasites exposed to selection increases in large flocks. Our results also showed a high dependence on the timing of treatment i.e. on the size of the refugia constituted by the free-living stages on the pasture.
The ecological consequences of seed size variation have been studied extensively in plants. Curiously, little attention has been paid to the qualitative and quantitative variation of the seed‐stored ...molecules and on their ecological significance. Here, we analysed the oil content and oil composition of ca. 200 weed seed species from agricultural fields in France based on single seed accessions, concentrating on interspecies differences and ignoring within‐species variation. The relationships between seed weight, oil %, fatty acids (FAs) and the energetic value of the seed and its antioxidant properties were also investigated. The antioxidant activity could contribute to protect the oily seed reserves from alteration over time. Among the species analysed, we found a considerable quantitative (oil%) and qualitative variation of FAs stored in the seeds. Such variation was largely related to the plant family of the different species, but intrafamily variation was also found. Heavier seeds contained less oil on a per gram basis than lighter seeds, suggesting a trade‐off between seed weight and oil ratio in the seed and that oil storage strategy depends on seed size. Moreover, oily seeds contained more polyunsaturated FAs. However, contrary to our hypothesis, we did not found a higher antioxidant capability in oily seed extracts than in non‐oily seeds, nor to the quantitative or to the qualitative variation of FAs in the seeds. Considering the role of these important trait variations on weed ecological strategies, such as germination period, seed predation rate and competition–colonisation trade‐off, could improve the sustainable management of weed communities.
We describe a new service model, the Orthopaedic Assessment Unit (OAU), designed to provide care for trauma patients during the COVID-19 pandemic. Patients without COVID-19 symptoms and isolated ...musculoskeletal injuries were redirected to the OAU.
We prospectively reviewed patients throughput during the peak of the global pandemic (7 May 2020 to 7 June 2020) and compared with our historic service provision (7 May 2019 to 7 June 2019). The Mann-Whitney and Fisher Exact tests were used to test the statistical significance of data.
A total of 1,147 patients were seen, with peak attendances between 11am and 2pm; 96% of all referrals were seen within 4h. The majority of patients were seen by orthopaedic registrars (52%) and nurse practitioners (44%). The majority of patients suffered from sprains and strains (39%), followed by fractures (22%) and wounds (20%); 73% of patients were discharged on the same day, 15% given follow up, 8% underwent surgery and 3% were admitted but did not undergo surgery. Our volume of trauma admissions and theatre cases decreased by 22% and 17%, respectively (
=0.058; 0.139). There was a significant reduction of virtual fracture clinic referrals after reconfiguration of services (
<0.001).
Rapid implementation of a specialist OAU during a pandemic can provide early definitive trauma care while exceeding national waiting time standards. The fall in trauma attendances was lower than anticipated. The retention of orthopaedic staff in the department to staff the unit and maintain a high standard of care is imperative.
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